Tanks (low temperature liquid tanks) in which a low temperature liquid is stored, such as liquefied natural gas (LNG) tanks or liquefied petroleum gas (LPG) tanks, are each equipped with a storage tank in which the low temperature liquid is stored and a support portion that supports the storage tank. To prevent heat from being input from the ground, a heat insulation is included in the support portion (bottom cold insulating structure).
Conventionally, foam glass, which has high rigidity and in which the effect of creep caused by a load applied from above is negligible in a manner similar to concrete, has been used as the heat insulation included in the support portion. Further, in recent years, a technique in which a margin including a sidewall of a storage tank is formed of a material in which the effect of creep is negligible, such as concrete, and a water- or cyclopentane-foamed heat insulation having higher cold insulating performance as shown in Patent Documents 1 and 2 is arranged inside the margin has also been proposed.